Princess Mako and Kei Komuro set to announce their engagement to the public on Sept. 3

Princess Mako, the eldest granddaughter of Emperor Akihito, and her longtime boyfriend, Kei Komuro, will speak to the press together on Sept. 3 to officially announce their engagement, the Imperial Household Agency said Thursday.

The announcement had originally been planned for July 8 but the couple decided to postpone it in the wake of damaging rains that lashed southwestern prefectures earlier in the month.

Earlier this month, the agency proposed that the princess and Komuro set another date for the announcement, according to the agency.

The new announcement date was fixed after adjusting the schedules for the Emperor, Empress Michiko, and the parents of the princess, Prince Akishino and Princess Kiko.

Princess Mako and Komuro, both 25, met five years ago when they were students at International Christian University in Tokyo, and Komuro reportedly proposed about a year after they started dating. He currently works at a law firm in the capital.

On the morning of Sept. 3, the Emperor is expected to carry out a procedure to approve their marriage. Agency chief Shinichiro Yamamoto will then hold a news conference to announce the couple’s engagement after reporting to the Emperor and Empress, as well as the princess’ parents, that he would make the announcement to the public.

It will be the first time for Princess Mako and Komuro to speak to the media together.

A traditional rite of betrothal called Nosai no Gi will be formalize the engagement. It will be followed by a number of ceremonies in the run-up to their expected 2018 wedding.

In previous cases, the engagement announcement of the Emperor’s daughter, Sayako Kuroda, had been delayed twice due to unexpected events.

The agency originally planned to announce her engagement to Tokyo Metropolitan Government employee Yoshiki Kuroda in November 2004. But it was postponed to Dec. 18 after a huge earthquake struck Niigata Prefecture. Then Princess Takamatsu, the Emperor’s aunt, died early on the rescheduled day, so the engagement announcement was pushed back further to Dec. 30.

The last marriage of a Japanese princess took place in October 2014, when Princess Noriko, a daughter of Emperor Akihito’s late cousin, Prince Takamado, tied the knot with Kunimaro Senge, the eldest son of the chief priest of Izumo Taisha, a Shinto shrine in Shimane Prefecture.

The Diet enacted a law in June to allow the 83-year-old Emperor to pass the throne to his elder son, Crown Prince Naruhito, in what would be Japan’s first abdication in two centuries.

The timing of the abdication has yet to be determined, but after the handover of the Chrysanthemum Throne, Prince Akishino, Princess Mako’s father, is set to become first in line to the throne.

Princess Mako is scheduled to travel to Hungary with Prince Akishino from Saturday on a private trip.